Duplex outlets, switches, and other electrical devices are frequently mounted to walls constructed of cement or aggregate blocks. To mount an electrical device in such a wall, the installer typically breaks a hole in a block at the desired location, with the hole large enough to accept an electrical box. The hole, typically made with a hammer and chisel, is usually somewhat larger than the box. Furring strips are then typically secured to the surface of the block wall to provide a brace for accepting the fasteners of a standard electrical box. The electrical box is aligned with its front face planar with the wall surface and the box fasteners driven into the furring strip to secure the box to the wall. The oversize hole is typically filled in by blowing pressurized foam, such as polyurethane foam, into the spaced between the box and surrounding block surface to seal the space between the box and the block. After the foam has cured, portions of it typically extend outwards of the block wall and from the base of the electrical box. This prior art method of installing an electrical device is illustrated in FIGS. 10–12. FIG. 10 depicts in exploded relationship an oversize hole 200 broken in the block wall 202, two furring strips 204 in position to be secured to the wall by fasteners 206, a prior art electrical box 208, a duplex receptacle 210, and a faceplate 212. FIG. 11 depicts the furring strips 204 secured to the wall, the prior art electrical box 208 secured to one of the furring strips 204 by a fastener 214, a duplex receptacle 210 and faceplate 212 in alignment with the electrical box 208, and foam 216 that has been used to fill the oversize hole. FIG. 12 depicts a completed installation of a prior art electrical box 208 to a block wall 202 including the furring strips 204 secured to the wall 202, the electrical box 208 secured to one of the furring strips 204, and cured polyurethane foam 216 that has been used to fill the oversize hole 200. With reference to FIG. 10, it should be apparent that this prior art method of providing an electrical box 208 on a block wall 202 is a cumbersome, labor intensive, time-consuming task that leads to an unattractive result. Typically the cured foam 216 extends well beyond the face of the wall 202 and it is difficult to trim the extending foam neatly. In a situation in which the wall will be covered with a finished surface, such as drywall or paneling, it is not important to have an attractive installation. But in those situations in which a finished surface is not applied, the prior art method leaves a very unattractive box. Furthermore, it is difficult in the prior art method to get the proper offset from the anticipated surface of the later installed finished layer, as the prior art box is mainly intended for installation on framed walls, and the fasteners that come with the box are not positioned to create a desired offset. The installer must therefore estimate the desired position of the electrical box to make it even with the finished wall.
It should be appreciated from the above description of installing an electrical box in a block wall that the procedure involves numerous steps and, as a result of the curing time for the foam, a substantial length of time. The installation requires two fastening steps, including fastening the furring strips to the block wall and then fastening the box to the furring strips. The current technique for installing an electrical box in a block wall therefore requires a great deal of time and effort. As a result of sealing the oversize hole with foam, the installed box is not very attractive to the eye as it is difficult to provide a smooth wall surface immediately surrounding the perimeter of the box. For these reasons, installation of an electrical box in a cement block wall is tedious and does not produce an attractive final result.
What is needed therefore is a device that reduces the time and effort involved in installing an electrical box in a cement block wall and provides an eye pleasing final result.